15,921

3² × 29 × 61

Starting at 15,921, the Collatz iteration reaches 1 after 146 steps. The first transition is 47764; the starting value is odd with 12 positive divisors.

Prime Factor Structure

Factorization String 3^2 × 29 × 61

Distinct Prime Factors 3

Square Status No

Abundance Measure Deficient

Analytical Properties

Total Divisors 12

Divisor Sum (σ) 24,180

Proper Divisor Sum 8,259

Digit Sum / Digital Root 18 (Root: 9)

Adjacent Primes #15919 ← → #15923

Radix Representation

Decimal	15921
Binary	11111000110001 (14 bits)
Octal	0o37061
Hexadecimal	0x3E31

Divisor Catalog (12)

1 3 9 29 61 87 183 261 549 1,769 5,307 15,921

Collatz Trajectory (146 steps to reach 1)

Iterative sequence n → n/2 (if even) or 3n+1 (if odd):

15,921 47,764 23,882 11,941 35,824 17,912 8,956 4,478 2,239 6,718 3,359 10,078 5,039 15,118 7,559 22,678 11,339 34,018 17,009 51,028 25,514 12,757 38,272 19,136 9,568 4,784 2,392 1,196 598 299 898 449 1,348 674 337 1,012 506 253 760 380 190 95 286 143 430 215 646 323 970 485 1,456 728 364 182 91 274 137 412 206 103

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